1. Field of Invention
The present invention relates to a display panel. More particularly, the present invention relates to an optical interference reflective element and repairing and manufacturing methods thereof.
2. Description of Related Art
Due to being lightweight and small in size, a display panel is favorable in the market of the portable displays and other displays with space limitations. To date, in addition to liquid crystal display (LCD), organic electro-luminescent display (OLED) and plasma display panel (PDP), a module of the optical interference display has been investigated.
U.S. Pat. No. 5,835,255 discloses a modulator array, that is, a color-changeable pixel for visible light which can be used in a display panel. FIG. 1A illustrates a cross-sectional view of a prior art modulator. Every modulator 100 comprises two walls, 102 and 104. These two walls are supported by posts 106, thus forming a cavity 108. The distance between these two walls, the depth of cavity 108, is D. The wall 102 is a light-incident electrode which, according to an absorption factor, absorbs visible light partially. The wall 104 is a light-reflective electrode that is flexed when a voltage is applied to it.
When the incident light shines through the wall 102 and arrives at the cavity 108, only the visible light with wavelengths corresponding to the formula 1.1 is reflected back, that is,2D=Nλ  (1.1)
wherein N is a natural number.
When the depth of the cavity 108, D, equals one certain wavelength λ1 of the incident light multiplied by any natural number, N, a constructive interference is produced, and a light with the wavelength λ1 is reflected back. Thus, an observer viewing the panel from the direction of the incident light will observe light with the certain wavelength λ1 reflected back at him. The modulator 100 here is in an “open” state.
FIG. 1B illustrates a cross-sectional view of the modulator 100 in FIG. 1A after a voltage is applied to it. Under the applied voltage, the wall 104 is flexed by electrostatic attraction toward the wall 102. At this moment, the distance between the walls 102 and 104, the depth of cavity 108, becomes d and may equal zero.
The D in the formula 1.1 is hence replaced with d, and only the visible light with another certain wavelength λ2 satisfying the formula 1.1 produces constructive interference in the cavity 108 and reflects back through the wall 102. However, in the modulator 100, the wall 102 is designed to have a high absorption rate for the light with the wavelength λ2. Thus, the incident visible light with the wavelength λ2 is absorbed, and the light with other wavelengths has destructive interference. All light is thereby filtered, and the observer is unable to see any reflected visible light when the wall 104 is flexed. The modulator 100 is now in a “closed” state.
As described above, under the applied voltage, the wall 104 is flexed by electrostatic attraction toward the wall 102 such that the modulator 100 is switched from the “open” state to the “closed” state. When the modulator 100 is switched from the “closed” state to the “open” state, the voltage for flexing the wall 104 is removed, and the wall 104 elastically returns to the original state, i.e. the “open” state, as illustrated in FIG. 1A.
FIG. 2A illustrates a schematic view of a conventional optical interference reflective structure which is operated in a passive matrix mode. As illustrated in FIG. 2A, an optical interference reflective structure 200 is a portion of a display panel and comprises a plurality of optical interference reflective elements. The optical interference reflective elements are constructed from light-incident electrode lines 202a, 202b and 202c arranged in rows and light-reflective electrode lines 204a, 204b and 204c arranged in columns. FIG. 2B illustrates a cross-sectional view taken along line AA′ in FIG. 2A, in which the three optical interference reflective elements made of the light-reflective electrode lines 204a, 204b, 204c and the light-incident electrode 202a are illustrated. As illustrated above, supports 206 are located between the light-reflective electrode lines 204a, 204b, 204c and the light-incident electrode 202a to form cavities, in which light is interfered.
FIG. 3A illustrates a schematic view of another conventional optical interference reflective structure, in which an optical interference reflective structure 200 has a short-circuited optical interference reflective element 302. FIG. 3B illustrates a cross-sectional view taken along line BB′ in FIG. 3A, which runs over the short-circuited optical interference reflective element 302. Because the conventional optical interference reflective elements are operated in the passive matrix mode, the potential differences for deforming the optical interference reflective element 302 is determined together by the potentials of the light-incident electrode line 202a and the light-reflective electrode line 204d. 
The optical interference reflective element 302 is short-circuited due to a structural fault, such as a defect in a dielectric layer of the light-incident electrode line 202a positioned in the optical interference reflective element 302. The short-circuit causes an unnecessary voltage drop and further affects the potential differences of other optical interference reflective elements in the same column (the light-reflective electrode line 204d) or in the same row (the light-incident electrode line 202a), thus spoiling the display of the whole optical interference reflective structure.